1. Field of the Invention
The present invention relates generally to data synchronization and, more particularly, to an improved asynchronous-to-synchronous parallel byte data transfer circuit.
2. Prior Art
U.S. Pat. No. 4,885,583 dated Dec. 5, 1989 of the present inventor describes a system that receives asynchronous serial messages of different lengths for different receivers and converts them to asynchronous parallel word messages. Besides data converting, this system also provides framing error and voltage and current out-of-range signals.
Co-pending U.S. application Ser. No. 286,196 entitles "Bus Receiver Powerup Synchronization and Error Detection Circuit" of the present inventor, filed Dec. 19, 1988, now U.S. Pat. No. 5,012,442, describes a system that synchronizes receipt of parallel data messages transferred asynchronously as three byte words preceded and succeeded by idle bytes so as to receive complete and not partial messages. Also, this system scrutinizes the messages for faults and for too many or too few bytes.
U.S. Pat. No. 4,977,599 dated Dec. 11, 1990 of the present inventor entitled "Improper Bit Combination Detection Circuit" describes combinational logic circuits used with a temporary storage device for holding data bytes which detects improper bits in both the lower and upper nibbles of the bytes. Combinations of bit patterns derived from both nibbles permit flagging the occurrences of a variety of bit errors existing in asynchronously transmitted parallel data bytes.
The present invention, as taught herein, may be used in cooperation with the structures claimed in the above patents and application.
A problem exists when destination code words and associated data words in a message transferred over a communications bus gets received by a data reception device in an asynchronous order and a need exists to file such data in a defined sequence to a plurality of end use devices such as meters and gauges in a vehicle. Effort was expended to develop means for solving this type of problem. That effort ended in the present invention.